A water-energy nexus analysis to a sustainable transition path for Ji-shaped bend of the Yellow River,China

The temporal and spatial dynamic change of energy water footprint reflects the use of water resources in the process of supplying energy. The spatio-temporal mismatch between energy and water resources in the Ji-shaped bend of the Yellow River has seriously restricted its development. In this paper, spatio-temporal variation in the water footprint of energy in the Ji-shaped bend of the Yellow River from 2000 to 2019 was characterized using the energy water footprint evaluation model. The spatial relationship between energy water footprint and regional water resources was analyzed using the standard deviation ellipse. Finally, the energy-water constraints in the study area were evaluated based on the water footprint stress index. The results were as follows. (1) The energy water footprint increased rapidly, and the energy structure has become more equitable. (2) The spatial distribution of energy water footprint is unbalanced, and the water footprint of fossil energy was higher in the east, but electricity was higher in the west. (3) Due to the growth of hydropower, electricity matches the available water resources to a greater extent than fossil energy. (4) The energy-water nexus is tense in the Ji-shaped bend of the Yellow River, so it is urgent to explore a sustainable transition path. Therefore, improving energy and water efficiency, optimizing the energy structure, and promoting low energy and water resource consumption patterns will be essential for facilitating sustainable development in the Ji-shaped bend of the Yellow River.     

Merriam's kangaroo rats (Dipodomys merriami) voluntarily select temperatures that conserve energy rather than water

Desert endotherms such as Merriam's kangaroo rat (Dipodomys merriami) use both behavioral and physiological means to conserve energy and water. The energy and water needs of kangaroo rats are affected by their thermal environment. Animals that choose temperatures within their thermoneutral zone (TNZ) minimize energy expenditure but may impair water balance because the ratio of water loss to water gain is high. At temperatures below the TNZ, water balance may be improved because animals generate more oxidative water and reduce evaporative water loss; however, they must also increase energy expenditure to maintain a normal body temperature. Hence, it is not possible for kangaroo rats to choose thermal environments that simultaneously minimize energy expenditure and increase water conservation. I used a thermal gradient to test whether water stress, energy stress, simultaneous water and energy stress, or no water/energy stress affected the thermal environment selected by D. merriami. During the night (i.e., active phase), animals in all four treatments chose temperatures near the bottom of their TNZ. During the day (i.e., inactive phase), animals in all four treatments settled at temperatures near the top of their TNZ. Thus, kangaroo rats chose thermal environments that minimized energy requirements, not water requirements. Because kangaroo rats have evolved high water use efficiency, energy conservation may be more important than water conservation to the fitness of extant kangaroo rats.     

Assessment of the Industrial Tomato Processing Water Energy Nexus: A Case Study at a Processing Facility

Increased demand for water and energy and growing recognition of environmental issues motivate awareness of how these resources are used in industry. Industrial tomato processing consumes substantial quantities of both water and energy. To understand how these resources are used in tomato processing and what opportunities exist for improving efficiency, a water energy nexus (WEN) assessment was conducted that accounted for the various ways energy becomes embedded in water during processing by motors, pumps, fans, and boilers. The WEN assessment was conducted at an industrial tomato processing facility that processed 265 metric tonnes of fruit per hour to develop a map of water and associated energy use at each processing step. A total of 1.29 billion kilograms (kg) of water were used for the processing season, with 870 million kg routed to flumes. The analysis identified the thermal energy used to generate steam for the various heat exchangers and evaporators used during processing as the greatest source of embedded energy in process water (778,000 gigajoules per season). The electrical energy embedded in the process water totaled 4.4 million kilowatt‐hours per season, over 80% of which was attributed to pumping. Moreover, the data were used to identify opportunities to improve efficiency by adjusting water loads on equipment and developing strategies for water and energy conservation and recovery. The baseline water and energy use data provided by the WEN assessment can enable additional modeling to assess resource efficiency measures and the life cycle impact of processed tomato products.     

Multifunctional TENG for Blue Energy Scavenging and Self‐Powered Wind‐Speed Sensor

Triboelectric nanogenerator (TENG) has been considered to be a more effective technology to harvest various types of mechanic vibration energies such as wind energy, water energy in the blue energy, and so on. Considering the vast energy from the blue oceans, harvesting of the water energy has attracted huge attention. There are two major types of “mechanical” water energy, water wave energy in random direction and water flow kinetic energy. However, although the most reported TENG can be used to efficiently harvest one type of water energy, to simultaneously collect two or more types of such energy still remains challenging. In this work, two different freestanding, multifunctional TENGs are successfully developed that can be used to harvest three types of energies including water waves, air flowing, and water flowing. These two new TENGs designed in accordance with the same freestanding model yield the output voltages of 490 and ≈100 V with short circuit currents of 24 and 2.7 µA, respectively, when operated at a rotation frequency of 200 rpm and the movement frequency of 3 Hz. Moreover, the developed multifunctional TENG can also be explored as a self‐powered speed sensor of wind by correlating the short‐circuit current with the wind speed.     

A High‐Resolution Approach to Mapping Energy Flows through Water Infrastructure Systems

Using data from the water service area of the East Bay Municipal Utility District in Northern California, we develop and discuss a method for assessing, at a high resolution, the energy intensity of water treated and delivered to customers of a major metropolitan water district. This method extends previous efforts by integrating hourly data from supervisory control and data acquisition systems with calculations based on the actual structure of the engineered infrastructure to produce a detailed understanding of energy use in space and time within the territory of a large‐scale urban water provider. We found significant variations in the energy intensity of delivered potable water resulting from seasonal and topographic effects. This method enhances our understanding of the energy inputs for potable water systems and can be applied to the entire delivery and postuse water life cycle. A nuanced understanding of water's energy intensity in an urban setting enables more intelligent, targeted efforts to jointly conserve water and energy resources that take seasonal, distance, and elevation effects into account.     

春小麦胚芽伸长过程中渗透调节与能量代谢

本文用PEG模拟水分亏缺对春小麦红芒麦和绵阳11号胚芽伸长过程中生长、膨压、渗透势、水势和渗透调节能力与ATP含量、能荷变化及能量代谢间的关系进行了研究。结果表明,通过降低能荷,改变分解代谢与合成代谢的比率,使渗透调节物质积累,增加了幼苗的吸水能力,从而使其在一定的ATP能量水平上维持缓慢生长;抗旱品种红芒麦在水分亏缺下成苗速率较快,能保持一定的ATP能量水平和能荷值,渗透调节和吸水能力都比较强。     

Net Zero Fort Carson: Integrating Energy,Water, and Waste Strategies to Lower the Environmental Impact of a Military Base

Military bases resemble small cities and face similar sustainability challenges. As pilot studies in the U.S. Army Net Zero program, 17 locations are moving to 100% renewable energy, zero depletion of water resources, and/or zero waste to landfill by 2020. Some bases target net zero in a single area, such as water, whereas two bases, including Fort Carson, Colorado, target net zero in all three areas. We investigated sustainability strategies that appear when multiple areas (energy, water, and waste) are integrated. A system dynamics model is used to simulate urban metabolism through Fort Carson's energy, water, and waste systems. Integrated scenarios reduce environmental impact up to 46% from the 2010 baseline, whereas single‐dimension scenarios (energy‐only, water‐only, and waste‐only) reduce impact, at most, 20%. Energy conserving technologies offer mutual gains, reducing annual energy use 18% and water use 15%. Renewable energy sources present trade‐offs: Concentrating solar power could supply 11% of energy demand, but increase water demand 2%. Waste to energy could supply 40% of energy demand and reduce waste to landfill >80%, but increase water demand between 1% and 22% depending on cooling system and waste tonnage. Outcomes depend on how the Fort Carson system is defined, because some components represent multiple net zero areas (food represents waste and energy), and some actions require embodied resources (energy generation potentially requires water and off‐base feedstock). We suggest that integrating multiple net zero goals can lead to lower environmental impact for military bases.     

Domestic water versus imported virtual blue water for agricultural production: A comparison based on energy consumption and related greenhouse gas emissions

The supply of water, food, and energy in our global economy is highly interlinked. Virtual blue water embedded into internationally traded food crops has therefore been extensively researched in recent years. This study focuses on the often neglected energy needed to supply this blue irrigation water. It provides a globally applicable and spatially explicit approach to the watershed level for water source specific quantification of energy consumption and related greenhouse gas (GHG) emissions of irrigation water supply. The approach is applied to Israel's total domestic and imported food crop supply of 105 crops by additionally including import-related transportation energy and emissions. Total energy use and related emissions of domestic crop production were much lower (551 GWh/422 kt CO₂-equivalents [CO₂e]) than those embedded into crop imports (1639 GWh/649 kt CO₂e). Domestic energy and emissions were mainly attributable to the irrigation water supply with artificial water sources (treated domestic wastewater and desalinated water, 84%). Transport accounted for 79% and 66% of virtually imported energy and emissions, respectively. Despite transport, specific GHG emissions (CO₂e per ton of crop) were significantly lower for several crops (e.g., olives, almonds, chickpeas) compared to domestic production. This could be attributed to the high share of energy-intensive artificial water supply in combination with higher irrigation water demands in Israel. In the course of an increasing demand for artificial water supply in arid and semi-arid regions, our findings point to the importance of including “energy for water” into comparative environmental assessment of crop supply to support decision-making related to the water–energy–food nexus.     

The Water Withdrawal Footprint of Energy Supply to Cities

Water footprints traditionally estimate water lost as a result of evapotranspiration (or otherwise unavailable for downstream uses) associated with producing a certain good, and the same embodied in trade across regions is used to estimate regional and national water footprints. These footprints, however, do not address risk posed to city energy supplies characterized by insufficient streamflow to support energy production, such as cooling water intake (e.g., withdrawals) at thermoelectric power plants. Water withdrawal intensity factors for producing goods and services are being developed at the national scale, but lack sufficient spatial resolution to address these types of water‐energy challenges facing cities. To address this need, this article presents a water withdrawal footprint for energy supply (WWFES) to cities and places it in the context of other water footprints defined in the literature. Analysis of electricity use versus electricity generation in 43 U.S. cities highlights the need for developing WWFES to estimate risks to transboundary city energy supplies resulting from water constraints. The magnitude of the WWFES is computed for Denver, Colorado, and compared to the city's direct use of water to offer perspective. The baseline WWFES for Denver is found to be 66% as large as all direct water uses in the city combined (mean estimate). Minimum, mean, and maximum estimates are computed to demonstrate sensitivity of the WWFES to selection of water withdrawal intensity factors. Finally, scenario analysis explores the effect of energy technology and energy policy choices in shaping the future water footprint of cities.     

Water and molecular chaperones act as weak links of protein folding networks: energy landscape and punctuated equilibrium changes point towards a game theory of proteins

Water molecules and molecular chaperones efficiently help the protein folding process. Here we describe their action in the context of the energy and topological networks of proteins. In energy terms water and chaperones were suggested to decrease the activation energy between various local energy minima smoothing the energy landscape, rescuing misfolded proteins from conformational traps and stabilizing their native structure. In kinetic terms water and chaperones may make the punctuated equilibrium of conformational changes less punctuated and help protein relaxation. Finally, water and chaperones may help the convergence of multiple energy landscapes during protein-macromolecule interactions. We also discuss the possibility of the introduction of protein games to narrow the multitude of the energy landscapes when a protein binds to another macromolecule. Both water and chaperones provide a diffuse set of rapidly fluctuating weak links (low affinity and low probability interactions), which allow the generalization of all these statements to a multitude of networks.     

The temperature dependence of erythrocyte water diffusion permeability

1. The activation energy of the diffusion water exchange in red blood cells increases with temperature. 2. Fetal blood has a higher activation energy for diffusion water exchange than adult blood. 3. Treatment of red cells with p-chloromercuribenzoate alters the activation energy and apparently allows a lipid and a protein pore pathway to be resolved. The permeability and activation energy of the treated cells is in the range found for lipid membranes; and the difference between treated and untreated cells, the "protein" pathway, has a diffusion activation energy comparable with that of free water. 4. A resolution of the discrepancies between the NMR methods of measuring diffusion water exchange is suggested.     

Effect of water restriction on energy and water balance and osmoregulation of the fruit bat Rousettus aegyptiacus

The energy budget, water balance and osmoregulation of the fruit bat, Rousettus aegyptiacus, were studied during normal hydration and during water restriction (oven-dried apple diet). The water input and output were balanced during both normal hydration and water restriction. The kidney of the fruit bat is well adapted to handle the water load from its fruit diet by excreting large volumes (14% of the body mass per day) of dilute urine (113±25 mosmol·kg H₂P^-1) as well as reducing urine volume (-95%) and increasing urine osmotic concentration (555±280 mosmol·kg H₂O^-1) during water restriction. The haematocrit, plasma haemoglobin and total protein concentrations did not increase during water restriction and heat exposure, suggesting the conservation of plasma volume. Gross energy intake was not alfected by water restriction. However, digested energy intake and digestibility were significantly reduced. The effective regulation of energy and water budgets during water restriction suggests that the fruit bat can cope with seasonal climatic changes and with variable fruit supply during various seasons.Abbreviations BM body mass - DEI digested energy intake - EWL evaporative water loss - GEL gross energy intake - NH normal hydration - T _a ambient temperature - WR water restriction     

Use of the doubly labeled water method for measurement of energy expenditure, total body water, water intake, and metabolizable energy intake in humans and small animals

The basis of the doubly labeled water method is measurement of the differential rates of disappearance of two isotopes of water (H2 18O and either 2H2O or 3H2O, administered at the start of the study) from body water. Published studies indicate that, in its current forms, this technique can be used to provide accurate and reasonably precise information on carbon dioxide production, total body water, and water intake in free-living humans and many small animals. Total energy expenditure can be calculated from carbon dioxide production with little loss of precision. Metabolizable energy intake can also be predicted, as the sum of total energy expenditure plus an estimate for the change in body energy stores during the measurement, but this prediction is unlikely to be accurate and precise unless the subject is in approximate energy balance.     

Blood-sucking bugs as a gentle method for blood-collection in water budget studies using doubly labelled water

During doubly-labelled water (DLW) experiments, blood collection by venous puncture may traumatize animals and consequently affect the animals' behaviour and energy budget. Recent studies have shown that blood-sucking bugs (Triatominae; Heteroptera) can be used instead of conventional needles to obtain blood from animals. In this paper, we validate the bug method in captive nectar-feeding bats, Glossophaga soricina, for water budget analysis by comparing the daily water flux estimated with the DLW method with values measured by an energy balance method. As the mean daily water flux of the DLW method was not significantly deviating from the expected value, blood-sucking bugs may substitute more invasive methods of blood collection in DLW experiments. Based on the DLW estimates, daily energy and water intake rates were calculated and compared to values measured with the energy balance method. The DLW method and the energy balance method yielded on average similar results regarding the daily energy intake (DLW method: 48.8+/-14.2 kJ d(-1) versus energy balance method: 48.1+/-9.9 kJ d(-1)) and daily water intake (DLW method: 13.7+/-2.4 mL d(-1) versus energy balance method: 14.7+/-3.0 mL d(-1)). Based on the calculated water and sugar intake per day, we estimated the sugar concentration of ingested nectar to equal on average 16.2+/-2.4% (mass/mass), which fell close to the measured sugar concentration of 17% (mass/mass) bats fed on during the experiment. We conclude that it is possible to extrapolate mean daily energy and water intake for animal groups, populations and species based on DLW estimates, but due to the large variance of results (low accuracy), it seems inadequate to calculate values for single individuals.     

The effect of diet on water and energy turnover rates of four Gerbillurus species in captivity

The effects of diets differing in energy and water content on the energy turnover rates and water flux of four Gerbillurus species have been examined in the laboratory. Gerbillurus tytonis. a dune species, had higher than predicted daily energy expenditure (DEE) and high water turnover rates (WTR) for a small desert mammal. The large Gerbillurus setzeri , which occurs on gravel plains, has slightly lower than predicted DEE and lower WTR than the other gerbil species studied. The Gerbillurus species examined have DEE and WTR that are affected by the protein content and potential water yield of food eaten. The importance of diet selection for water and energy budgets are discussed as adaptive strategies employed for survival and reproduction within the southern African arid zone.     

Life Cycle Energy Assessment of Alternative Water Supply Systems (9 pp)

Goal, Scope and Background This paper discusses the merging of methodological aspects of two known methods into a hybrid on an application basis. Water shortages are imminent due to scarce supply and increasing demand in many parts of the world. In California, this is caused primarily by population growth. As readily available water is depleted, alternatives that may have larger energy and resource requirements and, therefore, environmental impacts must be considered. In order to develop a more environmentally responsible and sustainable water supply system, these environmental implications should be incorporated into planning decisions. Methods Comprehensive accounting for environmental effects requires life cycle assessment (LCA), a systematic account of resource use and environmental emissions caused by extracting raw materials, manufacturing, constructing, operating, maintaining, and decommissioning the water infrastructure. In this study, a hybrid LCA approach, combining elements of process-based and economic input-output-based LCA was used to compare three supply alternatives: importing, recycling, and desalinating water. For all three options, energy use and air emissions associated with energy generation, vehicle and equipment operation, and material production were quantified for life-cycle phases and water supply functions (supply, treatment, and distribution). The Water-Energy Sustainability Tool was developed to inform water planning decisions. It was used to evaluate the systems of a Northern and a Southern California water utility. Results and Discussion The results showed that for the two case study utilities desalination had 2–5 times larger energy demand and caused 2–18 times more emissions than importation or recycling, due primarily to the energy-intensity of the treatment process. The operation life-cycle phase created the most energy consumption with 56% to 90% for all sources and case studies. For each water source, a different life-cycle phase dominated energy consumption. For imported water, supply contributed 56% and 86% of the results for each case study; for desalination, treatment accounted for approximately 85%; for recycled water, distribution dominated with 61% and 74% of energy use. The study calculated external costs of air pollution from all three water supply systems. These costs are borne by society, but not paid by producers. The external costs were found to be 6% of desalinated water production costs for both case studies, 8% of imported water production costs in Southern California, and 1–2% for the recycled water systems and for the Northern California utility's imported water system. Conclusion Recycling water was found to be more energy intensive in Northern than in Southern California, but the results for imported water were similar. While the energy demand of water recycling was found to be larger than importation in Northern California, the two alternatives were competitive in Southern California. For all alternatives in both case studies, the energy consumed by system operation dominated the results, but maintenance was also found to be significant. Energy production was found to be the largest contributor in all water provision systems, followed by materials production. The assessment of external costs revealed that the environmental effects of energy and air emissions caused by infrastructure is measurable, and in some cases, significant relative to the economic cost of water. Recommendation and Perspective This paper advocates the necessity of LCA in water planning, and discusses the applicability of the described model to water utilities.     

Digestive parameters and water turnover of the leopard tortoise

Leopard tortoises (Stigmochelys pardalis) experience wide fluctuations in environmental conditions and unpredictable availability of food and water within the Nama-Karoo biome. It was hypothesised that tortoises fed two diets differing in preformed water and fibre content would have differing food intake, gut transit rate, assimilation efficiency, faecal and urinary water loss, and urine concentrations. It was predicted that tortoises fed these contrasting diets would attempt to maintain energy and water balance by altering their digestive parameters. Leopard tortoises fed lucerne (Medicago sativa) had a low food intake coupled with long gut transit times, which resulted in the lowest amount of faecal energy and faecal water lost. Tortoises fed tomatoes (Solanum lycopersicum) had higher food intake and faster gut transit times, but more energy and water was lost in the faeces. However, daily energy assimilated and assimilation efficiency were comparable between tortoises fed the two diets. Urine osmolality was significantly different between tortoises on the two diets. Results indicate that leopard tortoises can adjust parameters such as transit rate, food intake, water loss and urine osmolality to maintain body mass, water and energy balance in response to a high fibre, low water content and a low fibre, high water content diet. This study suggests that this digestive flexibility allows leopard tortoises in the wild to take advantage of unpredictable food and water resources.     

Photothermal Catalytic Gel Featuring Spectral and Thermal Management for Parallel Freshwater and Hydrogen Production

Desalination processes often require large amounts of energy to create clean water, and vice versa for the generation of energy. This interdependence creates a tension between the two essential resources. Current research focuses on one or the other, which exacerbates water‐energy stress, while few tackle both issues jointly. Herein, a low‐carbon technology, H₂O–H₂ co‐generation system that enables concurrent steady freshwater and clean energy output is reported. The water‐energy coupled technology features a spectrally and thermally managed solar harvesting gel for photoredox and photoheating effects. This photothermal catalytic gel exploits interfacial solar heating for heat confinement, and localized plasmonic heating at the catalyst active sites to remarkably improve water and hydrogen production, thus maximizing energy value per area. To this end, a stand‐alone renewable solar desalination system is successfully demonstrated for parallel production of freshwater and hydrogen under natural sunlight. By doing so, the water–energy nexus is transformed into a synergistic bond that offers opportunities to better meet expected demand rather than acting in competition.     

Integral energy as a measure of soil-water availability

The available water capacity is the most commonly used parameter to quantify the amount of water readily available to plants. However, it does not directly describe the energy requirements of the plant to remove a unit amount of water from the soil at various moisture contents within the available range. We present the integral energy concept as an attempt to quantify this. It is calculated from the integral of a soil's water-retention curve. We demonstrate the calculation for different types of soil. The integral energy provides useful information regarding the amount of energy, and hence the availability of water to plants. The value appears to be more correlated with basic soil physical properties, such as clay and sand content, compared with the conventional available water capacity.     

Hydration of uracil and thymine methylderivatives: a Monte Carlo simulation

The simulation performed shows that under methylation of uracil and thymine NH-groups the interaction energy between a base and water (Uwb) is increased. It is also detected that the increase in this energy was observed in the 1st and the 3rd sectors. These conclusions do not confirm the assumption made in the literature on the character of an interaction between methylated bases and water. According to this assumption, when the NH-groups are methylated, the energy of Uwb in these sectors decreases as a result of the van der Waals interactions between a methyl group and water, whose energy compensates the increase in the Uwb energy due to the breaking of an H-bond. Regularity of water molecules near a hydrophobic group under the hydration of polar molecules is detected for the first time.